JP4923452B2 - Method for producing SiC single crystal - Google Patents

Description

The present invention relates to the production how the SiC single crystal.

  The SiC single crystal has high breakdown voltage and high electron mobility, and is expected as a semiconductor substrate for power devices. Conventionally, SiC single crystals are generally produced by a single crystal growth method called a sublimation method (improved Rayleigh method).

  In the modified Rayleigh method, a SiC raw material is charged into a graphite crucible, a seed crystal is mounted on the inner wall of the graphite crucible so as to face the raw material portion, and the raw material portion is heated to 2200 to 2400 ° C. to sublimate gas. The SiC single crystal is grown by recrystallizing the seed crystal on the seed crystal at a temperature several tens to several hundred degrees C lower than the raw material portion.

  In this improved Rayleigh method, the SiC powder raw material deteriorates with the growth of the SiC single crystal, so the growth amount is limited. Even if a means for adding the raw material powder during the growth is taken, since Si and C sublime instead of 1: 1 when SiC sublimates, if the raw material is added during the growth, the sublimation gas in the crucible The concentration fluctuates and becomes an obstacle to continuously producing crystals with high quality.

  On the other hand, Patent Document 1 discloses a technique for epitaxially growing SiC by CVD. This method uses a gaseous raw material, and can be continuously supplied with stable control of the composition of the raw material.

  However, also in the above method, as the SiC single crystal grows, the surrounding environment on the surface of the grown crystal changes and the crystal growth conditions change. For this reason, it has been difficult to maintain quality when the crystal is grown long (long growth).

  In order to cope with this problem, it is conceivable to apply pull-up growth in which a crystal is grown while pulling up as a conventional technique. Most commonly, there is a CZ method of Si. This method pulls up crystals from the melt, and growth is easily controlled at the solid-liquid interface.

  When this technique is applied to vapor phase growth such as SiC, for example, in Patent Document 2, the crucible and the seed crystal are driven independently in the vertical direction to control the temperature of the raw material and the seed crystal, thereby stably growing. Propose that. However, since it is actually vapor phase growth, it is expected that the source gas diffuses freely and crystals are precipitated at various locations, thereby causing deterioration of crystallinity and damage to the apparatus.

  For this reason, Patent Document 3 proposes a method of growing a crystal by arranging a guide member on the side surface of the crystal. Thereby, it is possible to reduce the wraparound of the source gas to the crystal side surface and to grow stably.

However, even in this method, a slight phenomenon was observed in which the source gas that had entered the gap adhered to the crystal side surface and the crystal diameter was enlarged.
Japanese National Patent Publication No. 11-508531 JP-A-6-298594 JP 2001-226197 A

The present invention has been made under these circumstances, and its object is to provide a manufacturing how the SiC single crystal can be obtained crystals of the desired diameter.

The method for producing a SiC single crystal according to claim 1 includes a first step of measuring a crystal diameter during crystal growth, and a second step of adjusting the crystal diameter measured in the first step to an arbitrary set value. At least the SiC single crystal is grown by arranging a guide member on the side surface of the crystal, and the measurement of the crystal diameter is performed when the source gas is passed through the guide hole of the guide member and the crystal is grown in the guide hole. From the difference between the pressure downstream of the guide hole and the pressure upstream of the guide hole in the raw material gas flow, the gas flow rate exhausted from the guide hole, or the gas flow rate exhausted from the guide hole, indirectly the crystal diameter It is characterized by the fact that
According to such a method for producing a SiC single crystal, a crystal having a desired diameter can be obtained by measuring the crystal diameter during crystal growth and adjusting the crystal diameter to an arbitrary set value.

As described in claim 2 , in the SiC single crystal manufacturing method according to claim 1 , the crystal diameter is adjusted to an arbitrary set value by changing the amount of the crystal inserted into the guide member. If it is, it is possible to control the diameter while growing.

As described in claim 3 , in the SiC single crystal manufacturing method according to claim 2 , the adjustment of the crystal diameter to an arbitrary set value increases the crystal diameter by deeply inserting the crystal into the guide member. If the crystal diameter is reduced by inserting it shallowly, it becomes possible to easily adjust the diameter without changing parameters relating to quality such as temperature change and pressure change.

As described in claim 4 , in the method for producing a SiC single crystal according to claim 1 , the adjustment of the crystal diameter to an arbitrary set value is performed by changing the temperature of the guide member. It is possible to easily adjust the aperture.

As described in claim 5 , in the method for producing a SiC single crystal according to claim 1 , the adjustment of the crystal diameter to an arbitrary set value is performed by changing a plurality of growth parameters. It is possible to adjust the aperture with excellent responsiveness and stability.

As described in claim 6 , in the method for producing a SiC single crystal according to claim 5 , the plurality of growth parameters include the amount of the crystal inserted into the guide member disposed on the side surface of the crystal and the source gas into the crystal. And at least one of the flow rate of the raw material gas to the crystal is used as a parameter having good responsiveness, the temperature of the guide member disposed on the side surface of the crystal, and the raw material gas in the guide member. Using any one of the pulling speeds of the crystal when growing while supplying as a parameter with poor responsiveness, the crystal diameter can be changed arbitrarily by changing a combination of a parameter with good responsiveness and a parameter with poor responsiveness. By adjusting to the set value, it becomes possible to adjust the aperture quickly and stably.

As described in claim 7 , in the method for producing a SiC single crystal according to claim 1 , the adjustment of the crystal diameter to an arbitrary set value is performed by using an inert gas or an etching gas as a raw material gas on the side surface of the crystal. If it is carried out by diluting with (1), it becomes possible to suppress the reduction or enlargement of the diameter during continuous growth.

As described in claim 8 , in the SiC single crystal manufacturing method according to claim 1 , the adjustment of the crystal diameter to an arbitrary set value causes a discharge between the side surface of the crystal and the guide member. If this is done, positive aperture control is possible.

As described in claim 9 , in the method for producing a SiC single crystal according to claim 1 , the adjustment of the crystal diameter to an arbitrary set value is a portion whose diameter is larger than an arbitrary set value on the side surface of the crystal. If it is performed by irradiating a laser beam, the aperture can be adjusted regardless of the growth conditions.

As described in claim 10 , in the SiC single crystal manufacturing method according to any one of claims 1 to 9 , in the second step, the adjustment of the crystal diameter and the growth of the SiC single crystal are performed simultaneously. Then, long growth can be realized efficiently.

In the method for producing a SiC single crystal according to any one of claims 1 to 10 , as described in claim 11 , the growth of the SiC single crystal is performed by continuously supplying a source gas. Real long growth can be realized.

As described in claim 12, in the manufacturing method of the SiC single crystal according to any one of claims 1 to 11, the growth of SiC single crystals is performed while pulling the crystal, changing the growth conditions Stable and long growth can be performed.

As described in claim 13, in the manufacturing method of the SiC single crystal according to any one of claims 1 to 12, when reducing the crystal diameter and the surface of the crystals so as to etching by an etching gas The aperture can be quickly reduced, and the effect is great when the aperture is large.

As described in claim 14 , in the method for producing a SiC single crystal according to claim 13 , after the etching of the crystal surface, particles remaining on the crystal surface are removed by a larger gas flow than during the etching, and then again. When growth is started, particles generated during etching can be removed and growth can be performed with high quality.

In the method for producing a SiC single crystal according to any one of claims 1 to 14 , as described in claim 15 , a guide in which the adjustment of the aperture is arranged on a side surface of the crystal is a deviation from a set value. If it is performed within 50% of the distance between the member and the crystal, stable fitting becomes possible.

As described in claim 16 , in the method for producing a SiC single crystal according to any one of claims 1 to 14 , the adjustment of the aperture is performed so that a deviation from a set value is within 2% of the crystal aperture. If it is performed within the range, the growth conditions can be stabilized.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, the schematic cross section of the manufacturing apparatus of the SiC single crystal in this embodiment is shown. FIG. 2 shows an enlarged view of the portion X in FIG. 1, that is, the portion where the SiC single crystal 14 grows from the SiC seed crystal 13.

  In FIG. 1, a cylindrical vacuum vessel 1 is arranged in an upright state. The vacuum container 1 includes a main container 2, an upper container 3 disposed on the main container 2, and a lower container 4 disposed below the main container 2. The inside of the main container 2, the inside of the upper container 3, and the inside of the lower container 4 are in communication. The raw material gas is supplied through the inside of the lower vessel 4 to the reaction vessel (the lower reaction vessel 5 and the upper reaction vessel 6) arranged inside the main vessel 2, and the grown crystal 14 is formed in the upper vessel. 3 is taken out from the inside.

  The upper container 3 is made of, for example, SUS (stainless steel), and an outlet 3 a for taking out the SiC single crystal 14 on which the crystal has grown is provided on the side surface. An exhaust pipe 7 is connected to the top plate 3 b of the upper container 3, and a vacuum pump (not shown) is connected to the exhaust pipe 7. The vacuum pump (evacuation system) can adjust the pressure in the vacuum vessel 1 and purge it.

  The main container 2 and the lower container 4 are made of, for example, quartz tubes. The diameter of the lower container 4 is smaller than that of the main container 2, and the main container 2 and the lower container 4 communicate with each other through the plate 2a. A gas introduction pipe 8 extending in the vertical direction is connected to the bottom plate 4 a of the lower container 4. A gas introduction pipe 9 extending in the horizontal direction is connected to the gas introduction pipe 8.

  A heat insulating material 10 is disposed on the wall surface inside the main container 2. In addition, a bottomed cylindrical lower reaction vessel 5 is arranged in an upright state inside the heat insulating material 10 in the main vessel 2. The lower reaction vessel 5 is made of graphite. A covered cylindrical upper reaction vessel 6 is disposed in the upper surface opening of the lower reaction vessel 5. Here, as a positional relationship between the lower reaction vessel 5 and the upper reaction vessel 6, the upper reaction vessel 6 having a covered cylindrical shape is covered with the lower reaction vessel 5 from the lower end opening side of the upper reaction vessel 6. Is arranged. At this time, the outer peripheral surface of the lower reaction vessel 5 and the inner peripheral surface of the upper reaction vessel 6 are separated by a predetermined distance. Further, the upper end of the lower reaction vessel 5 and the lid portion 6a of the upper reaction vessel 6 are separated from each other.

  A guide through hole (hereinafter referred to as a guide hole) 11 is formed at the center of the lid 6 a of the upper reaction vessel 6. Gas passes through the guide hole 11. In the present embodiment, a guide member is configured by the lid 6 a of the upper reaction vessel 6. Hereinafter, the lid portion of the upper reaction vessel 6 is referred to as a guide member 6a.

  A pedestal 12 is disposed above the upper reaction vessel 6. The pedestal 12 is composed of a cylindrical portion 12a and an enlarged diameter portion (disk portion) 12b, and the cylindrical portion 12a protrudes downward from a central portion of the lower surface of the plate-like enlarged diameter portion 12b extending in the horizontal direction. That is, a disc-shaped enlarged diameter portion 12b is formed on one end surface (upper surface) of the cylindrical portion 12a, and the enlarged diameter portion 12b has a larger diameter than the cylindrical portion 12a. A silicon carbide semiconductor substrate 13 serving as a seed crystal is attached (fixed) to the other end surface (lower surface) of the cylindrical portion 12a. Then, SiC single crystal 14 grows at the central portion in guide hole 11 using silicon carbide semiconductor substrate 13 as a seed crystal. Thus, the guide member 6 a is disposed on the side surface of the crystal 14.

Inside the vacuum vessel 1, a heat insulating material 15 is disposed under the lower reaction vessel 5. A raw material gas supply passage 15 a is formed in the heat insulating material 15. The gas from the gas introduction pipes 8 and 9 is introduced into the raw material gas supply passage 15a of the heat insulating material 15, and is supplied into the upper reaction vessels 5 and 6 through the raw material gas supply passage 15a. Specifically, a raw material gas necessary for SiC single crystal growth such as SiH ₄ and C ₃ H ₈ , an etching gas such as H ₂ , CF ₄ , and O ₂ , an inert gas such as Ar and He, and N ₂ And a dopant gas such as can be introduced. That is, as the source gas, for example, a mixture of monosilane (a gas containing Si) and propane (a gas containing C) is used.

Thus, the gas introduction pipes 8 and 9 constitute a mechanism for continuously supplying the source gas.
The pedestal 12 is fixed to the lower end of the shaft 16 extending in the vertical direction. The shaft 16 is connected to a vertical movement mechanism (crystal pulling mechanism) 17 so that the shaft 16 can be moved up and down by the mechanism 17. In other words, SiC grown by the upward movement of the shaft 16 from the state of FIG. 1 can be moved to the sample take-out chamber (upper container 3), and the seed crystal 13 is moved downward from the upwardly moved state to move the main container 2 Can be moved in. Furthermore, the growth crystal 14 is pulled upward at an arbitrary speed during growth. More specifically, as shown in FIG. 2, the height Ho that is half the thickness t1 of the guide member 6a (the length of the guide hole 11) is the standard growth surface height in this embodiment, and the lower surface of the crystal 14 The height of the pedestal 12 (crystal 14) is adjusted so that (growth surface) becomes the standard growth surface height Ho. In the present embodiment, the growth rate is monitored by an X-ray generator 21 and an image tube 22 which will be described later, and the lower surface of the crystal 14 is adjusted to the standard growth surface height Ho according to the growth rate.

  Further, a cylindrical member 18 is disposed on the upper surface of the upper reaction vessel 6 in FIG. 1, and a base 12 is disposed inside the cylindrical member 18. The cylindrical member 18 is made of graphite. In the cylindrical member 18, a large number of through holes 18 a are formed in the radial direction in a portion below the enlarged diameter portion (disk portion) 12 b of the base 12. The gas that has passed through the guide hole 11 escapes through the through hole 18a. The cylindrical member 18 slides in a state where the inner peripheral surface of the cylindrical member 18 and the outer peripheral surface of the enlarged diameter portion (disk portion) 12b of the base 12 are in contact with each other. In this way, the pedestal 12 moves up and down.

  In FIG. 1, a high-frequency induction coil (RF coil) 19 as a heating mechanism is wound around the outer peripheral portion of the vacuum vessel 1 at the arrangement height of the guide hole 11. Then, by energizing the coil 19, an induction current is passed through the outer periphery of the upper half of the seed crystal 13, the grown crystal 14 and the upper reaction vessel 6 during the growth to heat the upper reaction vessel 6 and the inside thereof. Can be done. Further, a high frequency induction coil (RF coil) 20 is wound below the high frequency induction coil 19 in the outer peripheral portion of the vacuum vessel 1. Then, by energizing the coil 20, the reaction vessels 5, 6 and the inside thereof can be heated. The upper and lower high-frequency induction coils 19 and 20 can be controlled (heated) independently. As shown in FIG. 1, the temperature profile in the vertical direction at the time of growth is lower on the upper side (guide hole 11 side) than the inside of the reaction vessel 5.

  Further, as a diameter measuring mechanism, an apparatus 21 for generating X-rays and an image tube 22 for receiving X-rays are provided outside the vacuum vessel 1, more specifically on the outer peripheral side of the high-frequency induction coil 19, and guide holes 11 (crystal growth chambers). ) Across the board. The X-ray generator 21 generates X-rays toward the guide hole 11, that is, the end on the growth surface side of the crystal 14 during growth. The image tube 22 receives the X-rays that have passed through the vacuum vessel 1 and outputs a signal corresponding to the intensity thereof. That is, X-rays are transmitted through the reaction vessel 6 and the crystal 14, and the transmission intensity distribution is observed by using the image tube 22 to capture the end on the growth surface side of the crystal 14 during growth as an image image as shown in FIG. Can be done. Specifically, the crystal (SiC) has a higher X-ray absorption rate than C (carbon: carbon) which is the material of the reaction vessel 6. Therefore, the SiC single crystal 14 and the graphite (carbon) reaction vessel 6 can be distinguished and observed. Thus, the X-ray generator 21 and the image tube 22 constitute an X-ray transmitter / receiver, and the X-ray generator / receiver (X-ray generator 21 and image tube 22) adjusts the crystal diameter during crystal growth. A crystal diameter measuring means for directly measuring is configured.

  In addition, a pyrometer 23 is installed in the shaft 16 of FIG. 1 and a pyrometer 24 is installed under the gas introduction pipe 8. The pyrometers 23 and 24 control the temperature in the base 12 and the reaction vessels 5 and 6. It can be measured.

Next, the manufacturing method of a SiC single crystal is demonstrated.
When growing the crystal, after disposing the seed crystal 13, the inside of the vacuum vessel 1 is evacuated and argon gas (Ar) is introduced through the gas introduction pipes 8 and 9. Thereafter, the high-frequency induction coils 19 and 20 are turned on to inductively heat the reaction vessels 5 and 6. Then, the temperature in the reaction vessels 5 and 6 is stabilized at a predetermined temperature (preferably around 2400 ° C. at which SiC can be sublimated). At the same time, the pressure in the guide hole 11 is set to a predetermined pressure. Then, the source gas is introduced into the reaction vessels 5 and 6 through the source gas supply passage 15a. This gas is supplied to the seed crystal 13 to start growth.

  At the time of growth, as shown in FIG. 2, the lower surface (growth surface) of the grown crystal 14 has a height (standard growth surface height) Ho that is half the thickness t1 in the guide hole 11 of the guide member 6a. During the growth, the pedestal 12 is pulled upward. On the other hand, part of the gas passes through the guide hole 11 and passes through the through hole 18a of the cylindrical member 18 of FIG. A part of the gas passes from the inside of the reaction vessel 5 between the outer peripheral surface of the reaction vessel 5 and the inner peripheral surface of the reaction vessel 6 toward the exhaust pipe 7.

When the source gas is supplied to the seed crystal 13 and the crystal grows and the crystal length reaches a predetermined value, the supply of the source gas is stopped. And the crystal | crystallization 14 is taken out from the extraction opening 3a of FIG.
Here, the adjustment method of the crystal diameter at the time of manufacture of a SiC single crystal is demonstrated using FIG.

  4A, 4B, and 4C show a series of steps when the diameter of the grown crystal 14 is enlarged during the growth. 5A, 5B, and 5C show a series of steps when the diameter of the grown crystal 14 is reduced during the growth.

  First, as shown in FIG. 4A, the enlargement / reduction of the crystal diameter is observed. Observation is performed with the X-ray generator 21 and the image tube 22 described above. When the crystal diameter is increased, control is performed to reduce the diameter as shown in FIG. Specifically, the insertion of the crystal 14 into the guide hole 11 is made shallow. As a result, the raw material gas that has reached the crystal side surface is diffused as it is to the back surface (upper surface) of the guide member 6a, and the enlarged diameter portion of the crystal is also sublimated (etched), thereby reducing the diameter. On the other hand, the source gas that has reached the lower surface of the crystal adheres and grows on the lower surface of the crystal as usual. And as shown in FIG.4 (c), the control of a diameter is loosened and it grows.

  On the other hand, when the aperture is reduced as shown in FIG. 5A, control is performed to increase the aperture as shown in FIG. 5B. This is contrary to the case of reduction, and the crystal 14 is inserted deeply into the guide hole 11. Thereby, the flow resistance of the gas for reaching the back surface (upper surface) of the guide hole 11 through the space between the inner surface of the guide hole 11 and the crystal 14 is increased, and the residence time of the gas on the crystal side surface is increased. As a result, the growth in the radial direction is promoted in the reduced diameter portion, and the crystal diameter is enlarged. Further, the source gas that has reached the lower surface of the crystal adheres and grows on the lower surface of the crystal. Next, as shown in FIG. 5C, growth is continued.

A high-quality and long SiC single crystal ingot can be produced by repeating these operations by hand during growth or continuously by automatic control.
In the present embodiment, the guide diameter 6a and the vertical movement mechanism 17 of FIG. 1 are used to adjust the crystal diameter to an arbitrary set value based on the crystal diameter measurement result by the crystal diameter measuring means (21, 22). Crystal diameter adjusting means for adjusting is configured.
[Example]
This will be described with reference to the steps shown in FIGS.

  First, the seed crystal 13 was attached to the pedestal 12, and the seed crystal 13 having a diameter (diameter) φ1 of 100 mm was disposed at a predetermined position. At this time, the seed crystal 13 was arranged so that the (0001) C-plane of 4H—SiC faced the guide hole 11 side. The inner diameter (diameter) of the guide hole 11 was 102 mm, and the distance Δd between the inner surface of the guide hole 11 and the seed crystal 13 (crystal 14) was 1 mm. The thickness of the guide member 6a (the length of the guide hole 11) was 20 mm, and the seed crystal lower surface (growth surface) was inserted into the guide hole 11 by 10 mm.

In this state, the inside of the vacuum vessel 1 was evacuated, and argon gas (Ar) was introduced from the gas introduction pipes 8 and 9 at a flow rate of 10 SLM. Thereafter, power was supplied to the high-frequency induction coils 19 and 20, and the reaction vessels 5 and 6 were heated to 2400 ° C. and heated. After that, when the temperature of the reaction vessels 5 and 6 is stabilized at 2400 ° C., the pressure in the vacuum vessel 1 is set to 2.66 × 10 ⁴ Pa, and the flow rate of the raw material gas and the like is adjusted by a mass flow controller. Introduced in. At the time of introducing the raw material gas, growth was started by flowing 1.2 SLM of SiH ₄ , 0.32 SLM of C ₃ H ₈ and ₃ SLM of argon gas (Ar). In addition, the X-ray generator 21 was driven simultaneously with the start of growth, and the crystal diameter and growth rate were measured. The pedestal 12 (crystal 14) was pulled up according to the growth rate, and the state where the crystal end was always inserted into the guide hole 11 by 10 mm was maintained.

  The diameter is slightly enlarged from the start of growth, and after 7 hours of growth for 5 hours, the diameter is 100.4 mm, the diameter is increased by 0.2 mm on one side, and the distance Δd between the crystal 14 and the inner surface of the guide hole 11 It reached 20% of (= 1 mm). Therefore, the crystal 14 was pulled up 5 mm from the guide hole 11 and the growth surface was kept at the insertion position of 5 mm. By maintaining in this state for 30 minutes, the crystal diameter (diameter) could be reduced to 100 mm again. Thereafter, the growth surface of the crystal 14 was inserted to a depth of 7 mm from the guide hole 11, and the growth was continued. By further growing in that state for 7 hours, the crystal diameter decreased to 99.6 mm. Therefore, the growth surface of the crystal 14 was inserted again to a depth of 10 mm from the guide hole 11, and the growth was continued.

By repeating these processes, continuous pulling growth for 50 hours was realized, and a SiC single crystal ingot having a growth amount of 65 mm could be obtained.
As described above, growth is performed while pulling up the crystal 14. Generally, in the growth of SiC, since the raw material is a gas, the diameter is enlarged / reduced due to the wraparound of the raw material gas or sublimation from the crystal, and the growth becomes unstable. In order to solve this, in the present embodiment, the aperture is observed, the aperture is adjusted to an arbitrary set value, and then the growth is performed. Specifically, X-rays are used for observation of the diameter, and the reaction containers 5 and 6 are observed through transmission. Regarding the control of the diameter, by changing the amount of the crystal 14 inserted into the guide hole 11, the flow of gas on the crystal side surface is controlled to adjust the diameter. By performing such a series of steps a plurality of times as necessary, a SiC single crystal can be grown with high quality over a long growth amount. That is, the diameter of the growth can be controlled, and the SiC single crystal can be continuously grown with high quality over a long growth amount.

As described above, this embodiment has the following features.
As a method for producing a SiC single crystal, the crystal diameter is directly measured during crystal growth (first step). Then, the crystal diameter measured in the first step is adjusted to an arbitrary set value (second step). Therefore, by measuring the crystal diameter during crystal growth and adjusting the crystal diameter to an arbitrary set value, a crystal having a desired diameter can be obtained (continuous long growth can be realized without deviating from the target value). ). Specifically, a high-quality SiC single crystal is formed by actively controlling the enlargement / reduction of the crystal diameter during growth without contacting (interfering with) the guide member 6a at a desired diameter in the crystal growth direction. Can grow. That is, by measuring the crystal diameter, it is possible to determine the direction of control of the diameter, and by continuing the growth while adjusting the diameter to the target value, the crystal does not adhere to the guide member 6a and from the target value. Continuous growth can be performed without detachment.

Further, as shown in FIG. 4B and FIG. 5B, since the adjustment of the crystal diameter and the growth of the SiC single crystal 14 are performed simultaneously, the long growth can be realized efficiently.
Moreover, since the growth of the SiC single crystal 14 is performed by continuously supplying the raw material gas, more efficient long growth can be realized by continuously supplying the raw material.

Further, since the growth of the SiC single crystal is performed while pulling up the crystal 14, stable long growth can be performed without changing the growth conditions.
Further, since the SiC single crystal is grown by arranging the guide member 6a on the side surface of the crystal 14, the diameter can be easily controlled.

  On the other hand, the measurement of the crystal diameter is performed using X-rays, and the crystal 14 inside the graphite reaction vessel 6 can be directly observed from the side surface of the crystal 14, thereby enabling accurate diameter control. Here, the measurement of the crystal diameter may be performed by directly observing the crystal 14 in the graphite reaction vessels 5 and 6 from the bottom surface of the crystal 14 using X-rays. In this case, accurate diameter control is possible. Become.

  In addition, the measurement position of the diameter by X-ray was the end on the growth surface side of the crystal 14 during growth. Therefore, the change in aperture can be measured efficiently even if the observation area is narrow. That is, it is only necessary to irradiate only a narrow region with X-rays, and the change in aperture can be measured efficiently even in the small X-ray generator 21 and the image tube 22.

  Further, the adjustment of the crystal diameter to an arbitrary set value is performed by changing the insertion amount of the crystal 14 into the guide member 6a. That is, the amount of gas flow to the back surface (upper surface) of the guide member 6a is controlled by adjusting the amount of crystal inserted into the guide hole 11 to adjust the diameter. In this method, the adhesion / sublimation of the crystal on the side surface of the crystal is controlled without changing the growth condition of the crystal surface. Therefore, it is possible to control the diameter while performing the growth.

  In particular, the adjustment of the crystal diameter to the set value is to increase the crystal diameter by inserting the crystal 14 deeply into the guide member 6a and to decrease the crystal diameter by inserting the crystal 14 shallowly. Therefore, by deepening the insertion of the crystal into the guide hole 11, the gas flow resistance to the back surface (upper surface) of the pedestal 12 is increased, and the adhesion of the gas on the crystal side surface is promoted to enlarge the diameter. In addition, by inserting it shallowly, the flow resistance is reduced and the aperture is reduced. In this way, it is possible to easily adjust the aperture without changing parameters related to quality such as temperature change and pressure change.

  Here, as shown in FIG. 4B, the adjustment of the aperture is performed within a range where the deviation Δt from the set value is within 20% of the distance Δd between the crystal 14 and the guide member 6a. In a broad sense, the deviation Δt from the set value is performed within a range within 50% of the distance Δd between the crystal 14 and the guide member 6a. That is, the deviation Δt of the aperture is set within 50% of the distance Δd between the crystal 14 and the guide member 6a. This is due to the following reason. As the diameter increases, the resistance of gas flow to the back surface (upper surface) of the guide member 6a increases, and the diameter increases at an accelerated rate. Moreover, since the gas easily flows when the diameter decreases, the diameter decreases at an accelerated rate. For this reason, if it exceeds 50%, the change speed of the caliber becomes larger than the fitting speed, and it is difficult to perform stable caliber control, but stable fitting is possible within 50%.

Alternatively, as shown in FIG. 4B, the adjustment of the diameter may be performed within a range where the deviation Δt from the set value is within 2% of the crystal diameter φ1. As a result, the amount of heat released to the pedestal 12 (the amount of heat released from the crystal 14) and the amount of heat radiation do not change significantly, and the growth conditions can be stabilized. Specifically, SiC grows at a high temperature of 2000 ° C., and heat radiation greatly affects the temperature distribution in the reaction vessels 5 and 6 due to the change in crystal diameter. If the temperature exceeds 2%, stable temperature control is achieved. It becomes difficult. If it is within 2%, wafer processing in the subsequent process is easy.
(Second Embodiment)
Next, the second embodiment will be described focusing on the differences from the first embodiment.

In FIG. 6, the schematic cross section of the manufacturing apparatus of the SiC single crystal in this embodiment is shown.
The main configuration of the apparatus is almost the same as that of the first embodiment, but the amount of light passing through the guide hole 32 is measured using the light amount measuring device 30 instead of the device using X-rays as the diameter measuring device. Thus, the diameter is indirectly measured (the distance between the crystal and the guide member 6a is indirectly measured by measuring the amount of light leaking from the guide hole 32). Specifically, the light quantity measuring device 30 is fixed to the shaft 16. Further, a slit 31 for light observation is formed in the enlarged diameter portion (disk portion) 12b of the base 12. The observed light includes radiation from the back (upper surface) of the guide member 6a and radiation from the reaction vessels 5 and 6 passing between the crystal 14 and the guide member 6a. The radiation light in the reaction vessels 5 and 6 is light emitted at a higher temperature than the radiation light on the back (upper surface) of the guide member 6a and can be observed separately. Therefore, the change in the distance between the crystal 14 and the guide member 6a (the inner surface of the guide hole 32) can be estimated by the change in the radiation light from the reaction vessels 5 and 6, and the change in the diameter can be estimated. Further, the guide hole 32 has a tapered shape extending in the pulling direction, and grows so that the diameter is slightly increased.

The growth is the same as in the first embodiment.
A method for adjusting the crystal diameter will be described with reference to FIGS.
FIGS. 7A, 7B and 7C show a series of steps when the diameter of the grown crystal 14 is enlarged during the growth. FIGS. 8A, 8B, and 8C show a series of steps when the diameter of the grown crystal 14 is reduced during the growth.

  First, as shown in FIG. 7A, the enlargement / reduction of the crystal diameter is observed. For example, when the crystal diameter is increased with respect to the target value as shown in FIG. 7A, control is performed to reduce the diameter as shown in FIG. 7B. In this case, the power of the upper high-frequency induction coil 19 in FIG. 6 is increased so that the guide member 6a is heated. As a result, the temperature of the guide member 6a is increased, and the temperature of crystal faces facing each other is intensively increased. As a result, etching occurs on the outer periphery of the lower end portion of the crystal 14 and the diameter is reduced. On the other hand, in the center portion of the lower surface of the crystal 14, the crystal temperature is not greatly changed because the radiation from the lower reaction vessel 5 and the heat radiation to the pedestal 12 are mainly effective. As usual, it adheres and grows on the lower surface of the crystal. Then, as shown in FIG. 7C, the diameter control is relaxed and the growth is performed.

  On the other hand, as shown in FIG. 8A, when the aperture is reduced with respect to the target value, control is performed to increase the aperture as shown in FIG. 8B. Contrary to the case of reducing this, the power of the upper high-frequency induction coil 19 in FIG. 6 is reduced to lower the temperature of the guide member 6a. As a result, the crystal side surfaces facing each other are also lowered in temperature, and growth in the radial direction is promoted in the reduced diameter portion, and the crystal diameter is expanded. Further, the source gas that has reached the lower surface of the crystal adheres and grows on the lower surface of the crystal. Next, the growth is continued as shown in FIG.

A high-quality and long SiC single crystal ingot can be produced by repeating these operations by hand during growth or continuously by automatic control.
[Example]
The process will be described with reference to FIGS.

  First, the seed crystal 13 was attached to the pedestal 12, and the seed crystal 13 having a diameter of 100 mm was disposed at a predetermined position. At this time, the seed crystal 13 was arranged so that the (0001) C-plane of 4H—SiC faced the guide hole 32 side. The guide hole 32 has an inner diameter of 102 mm on the lower end side and a diameter of 104 mm on the upper end side, and is widened in the pulling direction. The thickness of the guide member 6a (the length of the guide hole 32) was 20 mm, and the lower surface (growth surface) of the seed crystal was inserted into the guide hole 32 by 10 mm. The distance between the guide member 6a and the crystal 14 on the lower surface (growth surface) of the seed crystal is 1.5 mm.

In this state, the inside of the vacuum vessel 1 was evacuated, and argon gas (Ar) was introduced from the gas introduction pipes 8 and 9 at a flow rate of 10 SLM.
Thereafter, power was supplied to the high-frequency induction coils 19 and 20, and the reaction vessels 5 and 6 were heated to 2400 ° C. and heated. After that, when the temperature of the reaction vessels 5 and 6 is stabilized at 2400 ° C., the pressure in the vacuum vessel 1 is set to 2.66 × 10 ⁴ Pa, and the flow rate of the raw material gas and the like is adjusted by a mass flow controller. Introduced in. During the introduction of the source gas, growth was started by flowing 1.2 SLM of SiH ₄ , 0.32 SLM of C ₃ H ₈ and ₃ SLM of Ar. Further, the amount of light passing through the guide hole 32 from the start of temperature rise is measured, and the diameter of the crystal 14 is estimated.

During the growth, the pedestal 12 (crystal 14) was pulled up according to the growth rate, and the state where the lower end portion of the crystal 14 was always inserted into the guide hole 32 by 10 mm was maintained.
The diameter is slightly increased from the start of growth, and after 10 hours of growth for 7 hours, the diameter is 101.2 mm, and the diameter between the crystal 14 and the guide member 6a is increased by 0.6 mm on one side (= 1. 5%). Therefore, by increasing the power of the upper high-frequency induction coil 19 and maintaining it for 2 hours, the crystal diameter could be reduced to φ100 mm again. However, the growth rate was also reduced from 1.4 mm / h to 1.1 mm / h due to the rise in temperature. After that, the induction power of the upper high-frequency induction coil 19 was reduced again, and growth was performed.

When the tapered guide hole 32 is used, it can be pulled up even if the diameter is increased, so that the range of control can be widened and the growth during the control is facilitated.
By repeating this process, continuous pulling growth for 50 hours was realized, and a SiC single crystal ingot having a growth amount of 60 mm could be obtained.

  As described above, in the present embodiment, the crystal diameter is not measured using X-rays, but the crystal is grown in the guide hole 32 while passing the source gas through the guide hole 32 of the guide member 6a. The crystal diameter was indirectly obtained by measuring the amount of light passing through the guide hole 32 (the distance between the crystal 14 and the guide member 6a was measured). Since the measurement can be performed at a distance from the growth region, the diameter can be measured without affecting the growth.

  Further, the adjustment of the crystal diameter to an arbitrary set value is performed by changing the temperature of the guide member 6a (the adjustment of the diameter is performed by changing the temperature of the crystal). Therefore, it is possible to easily adjust the aperture.

In each of the above-described embodiments, X-ray or light quantity observation is used as the diameter measurement technique. However, the crystal diameter measurement technique may be as follows.
(1-1) As shown in FIG. 9, a plurality of X-ray transmitters / receivers (first transmitter / receiver 25a, 25b and second transmitter / receiver 26a, 26b) are arranged around the crystal. When measuring the crystal diameter using X-rays, the diameters are measured from a plurality of directions by a plurality of X-ray transmitters / receivers (25a, 25b, 26a, 26b) arranged around the crystal 14. You may do it.

  Alternatively, a pair of X-ray transmitters / receivers (25a, 25b) are arranged to be movable around the crystal. Then, the aperture may be measured from a plurality of directions by moving a pair of X-ray transmitters / receivers (25a, 25b) around the crystal 14. In this way, by observing from a plurality of directions, it is possible to observe the amount of change in the diameter depending on the position, and it is possible to measure the diameter more precisely.

  (1-2) As a method of measuring the crystal diameter, as shown in FIG. 10, when crystal growth is performed in the guide hole 11 while passing the source gas through the guide hole 11 of the guide member 6a, the source gas flow F1 From the difference between the pressure P1 downstream of the guide hole 11 and the pressure P2 upstream of the guide hole 11, the crystal diameter is obtained indirectly. Alternatively, the crystal diameter is obtained indirectly from the gas flow rate Q1 exhausted from the guide hole 11. Alternatively, the crystal diameter may be obtained indirectly from the gas flow velocity v exhausted from the guide hole 11. That is, the diameter is obtained using the flow F1 from the inside of the reaction vessels 5 and 6 to the upper side of the guide member 6a (base 12). Thus, the change in the distance between the crystal 14 and the guide member 6a is measured by measuring the parameter caused by the change in the flow F1 from the inside of the reaction vessels 5 and 6 to the upper surface of the guide member 6a. This method does not require a complicated mechanism and can easily measure the aperture.

  (1-3) As shown in FIG. 11, as a method for measuring the crystal diameter, the light emitter 41 is embedded in the heat insulating material 15 and the light from the light emitter 41 passes through the through holes 15b and 5a and the outer periphery of the guide hole 11 The light receiver 40 receives the light through a slit 42 provided in the base 12. A sound wave may be used instead of the light wave generated by the light emitter 41.

  Thus, when crystal growth is performed in the guide hole 11 while passing the source gas through the guide hole 11 of the guide member 6a, the amount of light waves or sound waves introduced toward the guide hole 11 that passes through the guide hole 11 is determined. The crystal diameter is obtained indirectly by measurement. Thus, by positively introducing light waves, sound waves, etc., the aperture can be stably measured regardless of the growth conditions.

  (1-4) As shown in FIG. 12, the crystal diameter is indirectly obtained by measuring the weight W and the growth amount L of the grown crystal 14 as a method for measuring the crystal diameter. That is, from the L value and the W value, it can be determined whether or not the crystal is grown in a columnar shape as shown in FIG. In this way, the diameter is estimated from the weight W and the growth amount L. Since the weight measurement can be easily performed at low cost, the diameter can be easily measured.

  (1-5) In a system that monitors the rate of crystal growth using X-rays, the amount of aperture expansion is measured from the change in growth rate. That is, as a method for measuring the crystal diameter, the speed of crystal growth is obtained using X-rays, and the crystal diameter is obtained indirectly from changes in the growth speed. More specifically, when the distance between the crystal 14 and the guide member 6a is narrowed, the raw material gas stays and the growth rate increases. As a result, the growth rate and the crystal diameter can be measured simultaneously, and the crystal diameter can be measured and controlled easily.

  (1-6) The measurement of the crystal diameter is a method using X-rays in the first embodiment, a method of measuring the amount of light passing through the guide hole 32 in the second embodiment, and ( A plurality of methods among the method 1-2), the method (1-3), the method (1-4), and the method (1-5) may be used. In a broad sense, a plurality of aperture measurement techniques described so far may be combined and executed. By using a plurality of caliber measuring methods, the caliber can be measured more strictly in a space that cannot be directly observed in the graphite reaction vessels 5 and 6.

These caliber measuring methods are properly used according to the purpose.
Further, in order to adjust the crystal diameter to an arbitrary set value, in each of the above embodiments, a method of changing the amount of crystals inserted into the guide member 6a and the temperature of the guide member 6a is used. Also good.

  (2-1) The crystal diameter is adjusted to an arbitrary set value by changing a plurality of growth parameters. By changing a plurality of growth parameters, it becomes possible to adjust the aperture with excellent responsiveness and stability.

  Here, the plurality of growth parameters include at least one parameter with good responsiveness and one with poor responsiveness, and the crystal diameter is changed by changing the combination of the parameter with good responsiveness and the parameter with poor responsiveness. Adjust to any set value. By combining a parameter with good responsiveness and a parameter with poor responsiveness, it becomes possible to quickly and stably adjust the aperture.

  Specifically, as parameters having good responsiveness, the insertion amount of the crystal 14 into the guide member 6a disposed on the side surface of the crystal 14, the partial pressure of the raw material gas into the crystal 14, and the flow rate of the raw material gas into the crystal 14 are the same. Use at least one of them. Thereby, the insertion amount of the crystal 14 into the guide member 6a changes the flow, and the partial pressure of the source gas directly changes the degree of supersaturation. The flow velocity affects the boundary layer. When these are changed, the growth is affected responsively. Further, the crystallinity is not deteriorated unless a significant change is made. This makes it possible to control the aperture with good responsiveness.

  On the other hand, as a parameter with poor responsiveness, any one of the temperature of the guide member 6a disposed on the side surface of the crystal 14 and the pulling speed of the crystal 14 when growing while supplying the raw material gas into the guide member 6a. Is used. The temperature of the guide member 6a warms the crystal side surface by radiation. This is necessary for a long time after heating the guide member 6a (reaction vessel 6). However, even if the temperature difference between the crystal side surface and the guide member 6a is increased, unlike the change in partial pressure or the like, the crystal surface is not significantly changed. Therefore, stable growth is possible. The pulling speed does not immediately change the gas flow, and the reaction as the aperture control is slow. This is different from the melt growth of Si or the like. However, it does not cause sudden movements or temperature changes. Therefore, it can grow stably.

  (2-2) As a method of adjusting the crystal diameter to an arbitrary set value, the raw material gas on the side surface of the crystal 14 is diluted with an inert gas or an etching gas. Thus, by locally reducing (thinning) the partial pressure of the source gas on the crystal side surface, it becomes possible to suppress the reduction and expansion of the diameter during continuous growth.

  (2-3) As a method for adjusting the crystal diameter to an arbitrary set value, as shown in FIG. 14, discharge is caused between the side surface of the crystal 14 and the guide member 6a. As a result, the temperature of the crystal side surface rises, and active aperture control becomes possible.

  (2-4) As a method for adjusting the crystal diameter to an arbitrary set value, as shown in FIG. 14, a laser beam is irradiated to a portion whose diameter is larger than an arbitrary set value on the side surface of the crystal 14. . In detail, in FIG. 4, it carries out by irradiating a laser beam between the side surface of the crystal | crystallization 14, and the guide member 6a. This makes it possible to adjust the aperture regardless of the growth conditions.

  (2-5) As described in the second embodiment, when the adjustment of the crystal diameter to an arbitrary set value is performed by changing the temperature of the guide member 6a, the temperature of the guide member 6a is adjusted. When the crystal diameter is reduced, the surface of the crystal 14 is also etched with an etching gas. Thus, the aperture can be quickly reduced, and the effect is great when the aperture enlargement amount is large. Here, after the etching of the crystal surface, after the particles remaining on the crystal surface are removed by a gas flow larger than that at the time of etching, the growth is started again. As a result, it is possible to remove particles and the like generated during etching and to perform growth with high quality. It should be noted that when the crystal diameter is reduced except when the adjustment of the crystal diameter to an arbitrary set value is performed by changing the temperature of the guide member 6a (other than the temperature adjustment of the guide member 6a), The surface may be etched with an etching gas.

These caliber control methods are properly used according to the purpose.
(Third embodiment)
Next, the third embodiment will be described with a focus on differences from the first embodiment.

FIG. 15 shows a longitudinal cross-sectional view of the main part of the SiC single crystal manufacturing apparatus in the present embodiment. The manufacturing apparatus used in the present embodiment has features in the pedestal 12, the lower reaction vessel 5, and the like. Some of the characteristic configurations are the contents disclosed in FIG. To do.

  In FIG. 15, the pedestal 12 has a cylindrical portion 12a and an enlarged diameter portion (disk portion) 12b, and an enlarged diameter portion 12b having a larger diameter than the cylindrical portion 12a is formed on one end surface (upper surface) of the cylindrical portion 12a. In addition, SiC seed crystal 13 is fixed to the other end surface (lower surface) of cylindrical portion 12a. The cylindrical portion 12 a has substantially the same diameter as the SiC seed crystal 13 and the SiC single crystal 14. The SiC seed crystal 13 is attached to the other end surface (lower surface) of the cylindrical portion 12a with an adhesive.

  The pedestal 12 is slidable in a state where the outer peripheral surface of the enlarged diameter portion 12b is in contact with the inner peripheral surface of the cylindrical member 18 (can move up and down in a state of being in close contact with each other. ). The pedestal 12 slides in a direction opposite to the growth direction, that is, upward, in the state where the outer peripheral surface of the enlarged diameter portion 12b is in contact with the inner peripheral surface of the cylindrical member 18 in the cylindrical member 18 during crystal growth.

  The guide member 6 a is disposed in the lower opening of the cylindrical member 18 and has a guide hole 11. The diameter φ7 of the guide hole 11 is smaller than the inner diameter φ5 of the cylindrical member 18, and the raw material gas toward the SiC seed crystal 13 passes therethrough. The guide member 6 a is located on the side surface of the crystal 14.

  The crystal diameter can be measured during crystal growth by the X-ray generator 21 and the image tube 22 as the crystal diameter measuring means shown in FIG. The vertical movement mechanism 17 as the crystal diameter adjusting means adjusts the crystal diameter by moving the pedestal 12 in the cylindrical member 18 so as to set the crystal diameter to an arbitrary set value based on the measurement result of the crystal diameter (FIG. 4 ( a) to (c), see FIGS. 5 (a) to (c)). Thereby, a crystal having a desired diameter can be obtained.

The crystal diameter measurement may be performed using other means, and the crystal diameter adjustment may be performed using other means.
The outer diameter (diameter) D1 of the enlarged diameter portion 12b in FIG. 15 is larger than the outer diameter D2 of the cylindrical portion 12a. Specifically, the difference between the outer diameter D1 of the enlarged diameter portion 12b and the outer diameter D2 of the cylindrical portion 12a (= D1− D2) is 10 mm or more and 150 mm or less.

  The source gas passes through the guide hole 11 of the guide member 6a and moves toward the SiC seed crystal 13. The pedestal 12 has a cylindrical portion 12a having substantially the same diameter as the SiC seed crystal 13 and the SiC single crystal 14, and the diameter of the cylindrical portion 12a. Since it has the enlarged diameter portion 12b having a larger diameter, the sliding portion (rubbed portion) between the cylindrical member 18 and the enlarged diameter portion 12b is formed from the guide hole 11 as compared with the case where a columnar pedestal is simply used. It is separated and the SiC polycrystal is less likely to adhere to the sliding portion due to the source gas that has passed through the guide hole 11. Further, since the pedestal 12 slides in a state where the inner peripheral surface of the cylindrical member 18 and the outer peripheral surface of the enlarged diameter portion 12b are in contact with each other, the raw material gas that has passed through the guide hole 11 is It is difficult to escape from the gap, and the SiC polycrystal hardly adheres to the sliding portion.

  As described above, the cylindrical member 18 and the enlarged diameter portion 12b of the pedestal 12 are less likely to stick due to the attachment of SiC polycrystal, so that the enlarged diameter portion 12b of the pedestal 12 moves smoothly up and down by the shaft 16 and the vertical movement mechanism 17. can do.

  In particular, since the difference between the outer diameter D1 of the enlarged diameter portion 12b of the base 12 and the outer diameter D2 of the cylindrical portion 12a is 10 mm or more and 150 mm or less, the sliding portion (rubbing portion) between the cylindrical member 18 and the enlarged diameter portion 12b. Is sufficiently separated from the guide hole 11, and the raw material gas that has passed through the guide hole 11 makes it difficult for the SiC polycrystal to adhere to the sliding portion. More specifically, when the difference between the outer diameter D1 of the enlarged diameter portion 12b and the outer diameter D2 of the cylindrical portion 12a is larger than 150 mm, the effect of preventing the SiC polycrystal from adhering to the sliding portion (rubbed portion) becomes larger. The whole apparatus becomes large and expensive. On the other hand, if the difference between the outer diameter D1 of the enlarged diameter portion 12b and the outer diameter D2 of the cylindrical portion 12a is smaller than 10 mm, the SiC polycrystal tends to adhere to the sliding portion.

  Further, the length (height) H1 of the cylindrical portion 12a of the base 12 is 5 mm or more and 100 mm or less. Thus, since the length H1 of the cylindrical portion 12a is 5 mm or more, the sliding portion (rubbed portion) between the cylindrical member 18 and the enlarged diameter portion 12b is separated from the guide hole 11 and has passed through the guide hole 11. The raw material gas makes it difficult for the SiC polycrystal to adhere to the sliding portion. More specifically, when the length (height) H1 of the cylindrical portion 12a is smaller than 5 mm, the SiC polycrystal tends to adhere to the sliding portion. On the other hand, if the length (height) H1 of the cylindrical portion 12a is larger than 100 mm, the effect of preventing the SiC polycrystal from adhering to the sliding portion (rubbing portion) becomes larger, but the entire apparatus becomes larger and expensive. .

  Further, the inner diameter φ6 of the lower reaction vessel 5 is equal to or smaller than the diameter φ7 of the guide hole 11 of the guide member 6a. Specifically, the difference (= φ7−φ6) between the inner diameter φ6 of the lower reaction vessel 5 and the diameter φ7 of the guide hole 11 is 30 mm or less. The lower reaction vessel 5 is a heated raw material gas supply cylindrical member that sends the heated raw material gas toward the guide hole 11, and is disposed in a state of being separated from the guide member 6a. In the lower reaction vessel 5, the raw material gas is heated and thermally decomposed.

  Thus, since the inner diameter φ6 of the lower reaction vessel 5 is equal to or smaller than the diameter φ7 of the guide hole 11 of the guide member 6a, it is difficult for the source gas to directly hit the guide member 6a. Therefore, the SiC polycrystal can be prevented from adhering to the guide member 6a. As a result, the SiC polycrystal adhering to the guide member 6a and the SiC single crystal 14 can be prevented from sticking, the diameter of the SiC single crystal 14 can be controlled smoothly by the installation of the guide member 6a, and continuously pulled and grown for a long time. (This is preferable for continuous growth for a long time). More specifically, when the inner diameter φ6 of the lower reaction vessel 5 is larger than the diameter φ7 of the guide hole 11 of the guide member 6a, the raw material gas is likely to directly contact the guide member 6a, and the viewpoint that the SiC polycrystal adheres to the guide member 6a. From the viewpoint of fixing the SiC polycrystal adhering to the guide member 6a and the SiC single crystal 14, it is not preferable in controlling the diameter of the SiC single crystal 14 by the installation of the guide member 6a, and the time is long. Continuous pulling growth becomes difficult.

In particular, in this production apparatus , since the difference between the inner diameter φ6 of the lower reaction vessel 5 and the diameter φ7 of the guide hole 11 is 30 mm or less, the aperture control of the SiC single crystal 14 by the installation of the guide member 6a is smoothly performed. The pulling growth can be continued continuously for a long time (which is more preferable for continuous growth for a long time). More specifically, if the difference between the inner diameter φ6 of the lower reaction vessel 5 and the diameter φ7 of the guide hole 11 is larger than 30 mm, the effect of preventing the SiC polycrystal from adhering to the guide member 6a is increased, but the outer periphery of the SiC single crystal 14 is increased. The growth rate of the portion is reduced, and the growth surface of the SiC single crystal 14 ′ has an extremely convex shape as shown by the alternate long and short dash line in FIG. 15, and the quality and productivity are likely to deteriorate (not preferable from the viewpoint of quality and productivity). .

  Further, as shown in FIG. 16 instead of FIG. 15, the heat insulating material 50 may be arranged on the surface (upper surface) on the downstream side of the source gas in the guide member 6 a. Specifically, the heat insulating material 50 is disposed in a space surrounded by the guide member 6a, the enlarged diameter portion 12b, the columnar portion 12a, and the cylindrical member 18. The heat insulating material 50 is porous and the raw material gas can pass therethrough.

  In this way, by disposing the heat insulating material 50 on the surface of the guide member 6a in the cylindrical member 18, heat escape from the guide member 6a is reduced by the heat insulating material 50, the temperature of the guide member 6a is increased, and the guide The adhesion of SiC polycrystal to the member 6a can be suppressed. As a result, the SiC polycrystal adhering to the guide member 6a and the SiC single crystal 14 can be prevented from sticking, and the diameter control of the SiC single crystal 14 by the installation of the guide member 6a is smoothly performed for a long time. (This is preferable for long-term continuous growth).

The schematic sectional drawing of the manufacturing apparatus of the SiC single crystal in 1st Embodiment. The enlarged view of the X section in FIG. The figure which shows an X-ray image. (A)-(c) is an image figure for demonstrating a manufacturing process. (A)-(c) is an image figure for demonstrating a manufacturing process. The schematic sectional drawing of the manufacturing apparatus of the SiC single crystal in 2nd Embodiment. (A)-(c) is an image figure for demonstrating a manufacturing process. (A)-(c) is an image figure for demonstrating a manufacturing process. The schematic cross-sectional view of the manufacturing apparatus of the SiC single crystal in another example. The schematic longitudinal cross-sectional view of the manufacturing apparatus of the SiC single crystal in another example. The schematic sectional drawing of the manufacturing apparatus of the SiC single crystal in another example. The schematic sectional drawing for demonstrating another example. The figure which shows the relationship between L value and W value for demonstrating another example. The schematic sectional drawing of the manufacturing apparatus of the SiC single crystal in another example. The schematic sectional drawing in the principal part of the manufacturing apparatus of the SiC single crystal in 3rd Embodiment. The schematic sectional drawing in the principal part of the manufacturing apparatus of the SiC single crystal in another example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 5 ... Lower reaction container, 6 ... Upper reaction container, 6a ... Guide member, 8 ... Gas introduction pipe, 9 ... Gas introduction pipe, 11 ... Guide hole, 12 ... Base, 12a ... Cylindrical part, 12b ... Expanded diameter part, DESCRIPTION OF SYMBOLS 13 ... SiC seed crystal, 14 ... SiC single crystal, 16 ... Shaft, 17 ... Vertical movement mechanism, 18 ... Cylindrical member, 21 ... X-ray generator, 22 ... Image tube, 32 ... Guide hole, 50 ... Heat insulating material.

Claims (16)

In the method for producing a SiC single crystal in which a SiC single crystal (14) is grown from a SiC seed crystal (13),
A first step of measuring the crystal diameter during crystal growth;
A second step of adjusting the crystal diameter measured in the first step to an arbitrary set value;
Having at least
The SiC single crystal is grown by arranging a guide member (6a) on the side surface of the crystal (14),
The measurement of the crystal diameter is performed when the raw material gas is allowed to pass through the guide hole (11) of the guide member (6a) and the crystal is grown in the guide hole (11). The difference between the pressure (P1) downstream of (11) and the pressure (P2) upstream of the guide hole (11), the gas flow rate (Q1) exhausted from the guide hole (11), or the guide hole (11 A method for producing a SiC single crystal, wherein the crystal diameter is indirectly obtained from the gas flow rate (v) exhausted from the gas. The SiC single unit according to claim 1 , wherein the adjustment of the crystal diameter to an arbitrary set value is performed by changing an insertion amount of the crystal (14) into the guide member (6a). Crystal production method. The adjustment of the crystal diameter to an arbitrary set value is to increase the crystal diameter by inserting the crystal (14) deeply into the guide member (6a) and to decrease the crystal diameter by inserting it shallowly. The manufacturing method of the SiC single crystal of Claim 2 characterized by these. Any narrowing combined to set values, said guide member manufacturing method of SiC single crystal according to claim 1, characterized in that is performed by changing the temperature of the (6a) of the crystal diameter. The method for producing an SiC single crystal according to claim 1 , wherein the adjustment of the crystal diameter to an arbitrary set value is performed by changing a plurality of growth parameters. The plurality of growth parameters are the amount of the crystal (14) inserted into the guide member (6a) disposed on the side surface of the crystal (14), the partial pressure of the source gas into the crystal (14), and the crystal (14). ) Using at least one of the flow rates of the raw material gas as a parameter having good responsiveness, the temperature of the guide member (6a) disposed on the side surface of the crystal (14), and the inside of the guide member (6a) Any one of the pulling speeds of the crystal (14) when growing while supplying the raw material gas is used as a parameter having poor responsiveness, and the parameter having good responsiveness and the parameter having poor responsiveness are combined. 6. The method for producing a SiC single crystal according to claim 5 , wherein the crystal diameter is adjusted to an arbitrary set value by changing. Said narrowing combined to any set value of the crystal diameter, according to claim 1, characterized in that is performed by diluting a source gas of an inert gas or an etching gas in the side surface of the crystal (14) A method for producing a SiC single crystal. Said narrowing combined to any set value of the crystal diameter, according to claim 1, characterized in that is performed by causing a discharge between the sides and the guide member of the crystal (14) (6a) A method for producing a SiC single crystal. The adjustment of the crystal diameter to an arbitrary set value is performed by irradiating a portion of the side surface of the crystal (14) whose diameter is larger than the arbitrary set value with a laser beam. Item 2. A method for producing a SiC single crystal according to Item 1 . The method for producing a SiC single crystal according to any one of claims 1 to 9 , wherein the adjustment of the crystal diameter and the growth of the SiC single crystal (14) are performed simultaneously in the second step. . The method for producing an SiC single crystal according to any one of claims 1 to 10 , wherein the growth of the SiC single crystal (14) is performed by continuously supplying a source gas. The method for producing a SiC single crystal according to claim 1 , wherein the growth of the SiC single crystal is performed while pulling up the crystal (14). The method for producing a SiC single crystal according to any one of claims 1 to 12 , wherein the surface of the crystal (14) is etched with an etching gas when the crystal diameter is reduced. The SiC single crystal according to claim 13 , wherein after the etching of the crystal surface, particles remaining on the crystal surface are removed by a gas flow larger than that at the time of etching, and then the growth is started again. Production method. The deviation (Δt) from the set value of the adjustment of the aperture is within 50% of the distance (Δd) between the guide member (6a) disposed on the side surface of the crystal (14) and the crystal (14). The method for producing a SiC single crystal according to claim 1 , wherein the method is performed within a range. The narrowing combined of the bore, the deviation from the set value (Delta] t) is, in any one of claims 1 to 14, characterized in that to perform in the range of within 2% of the crystal diameter (.phi.1) The manufacturing method of the SiC single crystal of description.

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